Our stock ROM (MetroPCS) apparently has the capability for Apps2SD, but it isn't enabled by default. Once you root, you can edit the build.prop file to enable that option:
Code:
ro.lge.capp_move_sdcard=true
If you join us over in the "all things root" section, I wrote a guide on rooting the phone. It isn't difficult, but requires many steps. The whole process is reversible, and you won't be voiding any warranty.
However, the best option will probably be to unlock the bootloader and install a custom ROM. I'm running CM10.1, and the ROM auto defaults to the external SD card as being the default storage. I download large games sometimes, and I don't ever have any issues.